Join Date: Jul 2007
Location: Anaheim, CA, USA
There are two BMW top cases that mount to the rack. The 49 liter is huge and has a built-in backrest. The 28 liter is smaller and doesn't come with a backrest, but you can buy one for it from BMW. Both are expensive. Both can be keyed to match your ignition key. They operate in a similar way to the GT side cases - with a handle for carrying and locking to the rack, and a flap for opening and locking shut.
You can buy non-BMW top cases from Givi, Coocase, and others, but they will require an adapter. You might also want to look at soft bags that mount to the rack.
I have the BMW 49 liter top case. It is a love/hate thing. I love the huge storage space it offers. It is the only case large enough to hold my backpack that I take to and from work.
I hate the gray look, the way it affects balance because it sits high and to the rear, and the way it catches side winds. I wouldn't give it up for anything though. For my daily commutes, I leave it attached and leave the side cases at home. I keep my helmet and jacket locked in it when I am at work, and my backpack in it when I am commuting. On the weekends I leave the top case at home.